Drought stress is a common challenge in maintaining a healthy lawn. This is especially true in locations with dramatic changes in seasonal weather conditions, called continental climates. 

The impact of drought stress on your lawn

While drought stress is an issue in itself, there are several secondary conditions that drought stress can trigger in your lawn. These include fungal diseases, insect and pest invasion, increased weeds, worsened soil compaction, and crown crushing.

1. Fungal diseases: Fungi, like Ascochyta Leaf Spot, also known as ‘Melting Out,’ arise when the lawn is stressed and its immune defense is weakened.
2. Insects and pests: When the lawn is weak and its root system is damaged by drought stress, it is easier for pests like voles, grubs, and billy bugs to invade, resulting in further irreparable damage to the turf.
3. Weeds: Drought stressed turf loses its ability to outcompete weeds. Tap root weeds like thistles and dandelions can better compete for limited resources.
4. Compaction: When the soil is dry, compaction is accelerated because it begins to harden and shrink.
5. Crown crushing: Mowing drought stressed turf, or even walking on it, crushes the fragile grass crowns so that it is killed permanently instead of just remaining dormant.

How do I know if my lawn is in drought stress?

There are four stages of drought stress:

• Stage One: The first sign of drought stress is when the lawn appears to have a bluish-gray/purple hue.
• Stage Two: During stage two, the lawn begins to look patchy due to uneven moisture retention. The ‘patchiness’ is the result of leaf blades curling to conserve moisture and require less energy.
• Stage Three: The lawn enters pre-dormancy during stage three, grass will lose its color and appear faded before significant browning occurs.
• Stage Four: When the lawn is in the final stage of drought stress it re-enters dormancy and will be almost completely brown.

You can confirm drought stress by performing a couple of quick tests. The footprint test entails walking across the grass – if it does not return to its position after a few minutes and remains flat and matted, it is evidence of drought stress. You can also use the screwdriver test by pushing a screwdriver or other instrument into the ground, at least 3 to 4 inches deep. If the instrument does not have any dirt or wet soil stuck to it when you remove it, the lawn is in drought stress. 

During stages one and two of drought stress, the lawn can still recover quite quickly, but once in stage three to four, it may be more difficult to mitigate the effects. Here’s how you can get the lawn back on track:

1. Begin frequent deep watering (extended periods, 20-30 minutes per zone), ideally in the early morning between 4:00-8:00 AM.
2. Avoid mowing until the grass begins to recover, and once it does, raise your mower height to 3 inches or higher. 
3. Try not to walk on or use the yard while the lawn is recovering to prevent further damage.
4. Liquid aeration – our aeration service doesn’t cause further damage or stress to the lawn like mechanical, or core, aeration. It also introduces additional nutrients to help recharge the soil as well as encouraging biological activity to give the lawn a much-needed boost.

I water regularly – why is my lawn suffering from drought stress?

Regular watering often isn’t enough to prevent drought stress in your lawn. In Montana, plants, including your lawn, rely on deep ground moisture reserves resulting from snowfall during the winter. If winter conditions don’t build enough water stores, summer watering must be increased to compensate. However, there are also other considerations that may affect how your lawn retains water.

1. Re-think your watering practices: Shallow, frequent watering leads to moisture evaporating too quickly and inhibiting deeper root growth. Practicing deep watering will cause the roots to grow deeper and prevent moisture loss.
   • Ask us for a rain gauge or place an empty tuna can in the yard to measure how much water your lawn is getting – we recommend around 1.5 inches per week!
2. Sprinkler coverage: Check for broken sprinkler heads or uneven overlap between zones, and have them rotated or adjusted regularly.
3. Soil quality: Not having enough top soil, poor quality soil, and lack of organic material contribute to drought stress because it has less ability to store moisture and the lawn can’t grow deep roots.
4. Soil compaction: Compacted ground can cause water to pool on the surface rather than be absorbed into the soil. Ask us about our Liquid Aeration service!

Understanding drought stress is vital to keeping cool season grasses healthy during the short growing season. It is even more important to know that just because your lawn is being watered, doesn’t necessarily mean it is safe from drought – applying the right watering practices and accounting for environmental conditions is essential. If you are unsure if your lawn is suffering from the effects of drought stress, we’re only a call away!